Technology Questions and Answers

Answer: D

Charles Babbage designed the Analytical Engine.

Conceived in 1837, it had a store for numbers, a mill to compute with them, punched-card input and conditional branching - the elements of a general-purpose computer. It was never built in his lifetime.

Answer: A

ARP stands for Address Resolution Protocol.

It finds the hardware MAC address matching a known IP address on a local network, by broadcasting a request that the owner of that address answers. Without it a packet could not be delivered on the final hop.

Answer: C

PLC stands for programmable logic controller.

It is a ruggedised industrial computer that reads sensors and drives motors, valves and relays on a factory floor. It replaced banks of hard-wired relays, and its logic is usually written as a ladder diagram.

Answer: B

PDF stands for Portable Document Format.

Adobe created it in 1993 so that a document would appear identically on any system, embedding fonts and layout in the file itself. It became an open ISO standard in 2008.

Answer: C

SMPS stands for switch mode power supply.

It converts mains AC to the low DC voltages a computer needs by switching at tens of kilohertz rather than using a heavy mains transformer, which makes it far lighter and more efficient than a linear supply.

Answer: C

Computers within a limited distance, connected to each other, form a local area network.

A LAN covers a building or campus and is owned by one organisation. A WAN spans a much greater distance and usually uses leased lines or public networks between its sites.

Answer: D

IPv4 addresses are 32 bits long.

They are written as four decimal numbers, each a byte, as in 192.168.1.1. That gives about 4.3 billion addresses, which ran out; IPv6 uses 128 bits and effectively cannot.

Answer: B

A JPG is a format for an image file.

JPEG compresses photographs by discarding the fine detail the eye notices least, achieving ten- or twentyfold reduction. Because the loss is cumulative, an image should be edited in a lossless format and saved as JPEG only at the end.

Answer: A

DPI stands for dots per inch.

It measures the resolution of a printer or scanner. 300 dpi is normal for documents and 600 or more for photographic printing; screen resolution is measured in pixels per inch instead.

Answer: D

All of these are electronic payment systems: credit cards, digital wallets and electronic cheques.

Card payment is much the largest by value; digital wallets store credentials for quick payment; and electronic cheques carry an instruction to debit an account, with a digital signature in place of a written one.